1. Field of the Invention
The present invention relates to a toroidal core for manufacturing pneumatic tires, which is used throughout formation of a green tire up to completion of its vulcanization.
2. Description of the Related Art
For manufacturing high performance pneumatic tires in a highly efficient and inexpensive manner, there has been proposed a method in which at least one rubber-coated cord is braided around a core which comprises a rigid body having a toroidal shape, so as to form at least one ply of radial carcass layer. Another rubber-coated cord is helically wound onto the radially outer side of the carcass layer so as to form at least one belt layer. A tread rubber in the form of unvulcanized rubber strip is wound onto the carcass layer and the belt layer to thereby form a green tire. Subsequently, the core together with the green tire supported thereon is transferred into a curing mold so as to perform vulcanization of the green tire.
According to the above-mentioned proposal, after vulcanization of the green tire has been completed, it is necessary to remove the core from the vulcanized tire. Thus, JP 6-28,863 B discloses a segmented toroidal core which is composed of a plurality of core segments. In this instance, when a green tire is to be formed on the core, the core segments are brought into tight contact with each other and arranged in the circumferential direction so as to form the toroidal core. The core segments are arranged so that they can be retracted radially inwards and sequentially removed from inside of the tire which has been subjected to vulcanization. There is a strong demand in the industry, for an improved segmented core for manufacturing pneumatic tires, which is highly suitable for practical use.